More particularly, in such a sorting machine, each letter whose destination has already been determined, is positioned vertically in a pocket. The pockets are fed on a carousel and their bottoms are opened above the output unit sufficiently to release each letter. At this output unit the letters are stacked flat in a box which serves for their transport to subsequent processing.
The device for inclining and stacking flat objects thus has to receive the letter vertical and deflect it so that it arrives horizontally in the box, where the letters should be stacked flat in a satisfactory manner. The deflection and stacking must be effected correctly, regardless of the rigidity of the letter, which may be a relatively flexible single sheet such as a leaflet or a relatively stiff magazine, and of which the material forming the envelope of the letter may be of various kinds, in particular paper or a plastics film.
Moreover, the device should observe limitations on space. In the invention the difference in height between the bottom of the pocket and the bottom of the box is less than or equal to about 600 mm.
Finally, it should avoid any jamming of the letter in the device with resultant clogging. In fact, at present "sticking" effects are observed in such devices, a letter sticking to the deflecting surface because of a kind of suction effect during the descent of the letter against the surface.